Transcript Manure storage, handling and application practices which

Manure Storage, Handling and
Application Practices which Mitigate
GHG Emissions for Hog Operations
Bruce T. Bowman
Chair, CARC Expert Committee
on Manure Management
Workshop on
Climate Change Strategy in the Hog Industry
Hull, QC
December 9, 2002
A Few GHG Statistics
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Agriculture accounts for 10–12% of GHG emissions in Canada.
With no mitigation, agriculture emissions expected to be 18%
above 1990 levels by 2010
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Relative importance in Agriculture
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Carbon dioxide – 11%
Methane – 36%
Nitrous oxide – 53%
From:
GHG Mitigation Strategy
for Can. Hog Industry
– June 2002
82% (est.) of GHG emissions for hogs comes from
manure management
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62% from methane
20% from nitrous oxide
9% from enteric fermentation (55 – 73% for ruminants)
Manure Management Objectives
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Odour control
Nutrient retention / re-use (recycling) (ammonia loss)
Pathogen reduction
Greenhouse gas emissions (CH4, N2O)
Land, labour or capital requirements
Energy efficiency
Animal / human health and performance considerations
Relative importance of these objectives is farm-specific
Optimizing only 1 objective at a time will negatively impact
on others – must use system approach
Factors Affecting GHG
Emissions from Manure
GHG production largely due to microbial processes
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Factors affecting microbes
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Aeration, moisture, temperature, nutrient sources
Livestock type (CH4 -
manure only - swine greatest)
(inc. enteric (direct) methane emissions - beef)
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How it is stored (slurry vs solid - aeration)
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Closed / open containment
How it is applied on the field (surface, injected)
 Timing, amount, compaction
Animal diets (ionophores - suppress CH4 production)
Ammonia Emissions from Manure
Include ammonia in ghg management strategy
Valuable nutrient
 Toxic substance (CEPA)
 Links to nitrous oxide production
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NH4+ ↔ NH3 + H+
K = [NH3] [H+] / [NH4+]
Factors
 Slurry pH (pK = 9.3; 50% NH3, 50% NH4+)
 Temp.-dependent If T↑ more NH3
 Air Flow
 C/N ratio
 Supply of NH4+ ions, urea or organic N
Nitrification & Denitrification
Nitrous Oxide Production
Nitrification
Oxidation
ammonium
nitrate
Denitrification
Nitrification &
denitrification are
mesophilic processes
30° - 40°C
Reduction
nitrate
nitrogen gas
1. MANURE COLLECTION & STORAGE
Manure Collection & Storage
to Minimize GHG Emissions
Remove manure from barn when fresh
…. minimizing water volumes … and
… transfer into a closed vessel / tank
BENEFITS
 Minimize odour production (NH3, VOCs)
 Minimize ammonia losses (toxic substance – CEPA)
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Improve air quality in barn – healthier for hogs and for
humans.. Improved performance
Manure Collection & Storage
to Minimize GHG Emissions
Remove manure from barn when fresh
…. minimizing water volumes … and
… transfer into a closed vessel / tank
BENEFITS
 Minimize GHG emissions from closed storage
 Little losses of CH4 or N2O
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Conserve nutrients & organic matter (carbon)
 Methane capture & energy recovery
 Minimize N losses (NH3, N2O) (closed systems)
Manure Collection & Storage
to Minimize GHG Emissions
Remove manure from barn when fresh
…. minimizing water volumes … and
… transfer into a closed vessel / tank
BENEFITS
 Avoid gas accumulations below
pens – explosions
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Avoid deterioration of cement
 H2S becomes sulfurous acid
vapour in presence of moisture
Ammonia Losses Influenced by the Retention
Time in Swine Housing
Management System
Slotted floor over pit
Daily scraping to pit
Gravity incline to pit
Retention on Barn Floor
NH3 Loss
~ 1 hour
~ 1 day
~ 1 week
5 - 9%
19 - 21%
27%
(Burton and Beauchamp, 1986)
Prompt removal to storage conserves N (ammonia)
Solutions For
Existing Lagoon Storages
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Negative Air Pressure Covers can reduce:
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GHG & ammonia emissions
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Odour release (does not change odour production)
BUT - doesn’t stop anaerobic processes in lagoon
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Uncovered Lagoon
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Can keep surface aerobic – difficult to stop anaerobic
generation of N2O & CH4 at greater depths
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NH3 loss reduced if pH → 7.0 (neutral).. BUT H2S
production will increase as pH decreases.
2. MANURE TREATMENT
Manure Treatment to
Minimize GHG Emissions
Two Choices
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“Dry” Systems –> Composting
> 65% moisture - de-water or add bulking agents
 Nitrification/Denitrification inhibited in 50° - 65°C range
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“Wet” Systems –> Anaerobic Digestion
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10% solids (> 90% moisture) – hog manures
Manure Treatment to
Minimize GHG Emissions
Dry System – In-vessel Composting
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Inside closed vessel, or inside building
- Reduce gaseous losses, odour (incl. NH3)
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Large volume reduction (40 – 60% reduction)
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Effective for killing pathogens (60° - 65°C)
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Product less likely to produce N2O when land applied
(Dr. John Paul, Transform Composting)
Manure Treatment
Composting
Dry System – In-vessel composting
Rotating Cylinder (8’ x 24’)
– Texas A&M Univ.
Transform Composting –
Abbottsford, BC
Tested in early 1990’s before ghg’s
Covered building - controlled
Manure Treatment
Rotary Vessel Composting
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Rapid initial treatment (3-4 days) @ 3-4 revs/hour
Control airflow
 Keep aerobic – prevent CH4 or N2O production
 Minimize NH3 losses – minimize odour
Moisture content < 65% (pre-dry or add bulking agent)
8’ x 24’ vessel for 400 cow herd (continuous flow)
Also Canadian developer of rotary composting technology
Concerns
 Static outdoor curing – CH4 emissions (anaerobic zones)
can increase several fold!
(Dr. C. Wagner-Riddle, pers. Comm, 2002)
Manure Treatment
Composting
Open-air composting - several problems
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Considerable N losses (ammonia, odour)
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CH4 & N2O emissions if anaerobic zones in pile
– turn pile on regular basis until curing completed
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Runoff losses if not covered (crust formation)
BEST to compost on covered cement pad to minimize
leaching & volatilization losses
Manure Treatment
Anaerobic Digestion
Liquid Systems
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Load daily from barn – no intermediate storage
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Closed system – no nutrient, gaseous losses
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Capture CH4 – generate electricity, heat
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Odours, pathogens greatly reduced
Manure Treatment
Anaerobic Digestion
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Low Tech
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High Tech
Manure Treatment
Anaerobic Digestion
Benefits
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Reduce odours & pathogens by 90% (mesophilic)
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All nutrients preserved during treatment (GHGs, NH3)
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Co-generation (electricity, heat)
 Energy independence (costs, brown-outs)
 Green credits (emission trading)
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N is conserved.. Closer N:P ratio for crop utilization
Manure Treatment
Anaerobic Digestion
Additional Benefits
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Homogeneous product
 More N in mineral form (50% C to methane)
 More predictable plant availability
 More uniform land application
 Increased flexibility for further treatment &
managing nutrients
– IF have excess nutrients, separate solids  organic
amendments / org. fertilizers
(off-farm value-added products, pellets, granules)
3. LAND APPLICATION
Land Application Practices
to Minimize GHG emissions
Liquid manure
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Inject in upper root zone
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Minimize exposure with air
Match applied nutrients to crop needs
 Amounts
& Timing
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Apply uniformly - moderate volumes
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Apply under well-aerated conditions
 Minimize
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compaction
Avoid application just before/after rain
Land Application Practices
to Minimize GHG emissions
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Nitrous oxide can be produced by
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Oxidation of ammoniacal N (NH4+, NH3)
Reduction of nitrate (NO3) – avoid anaerobic
Sources
N fertilizers
 Livestock manures
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Tillage Systems – no clear differences
Land Application Practices
to Minimize GHG emissions
DON’TS
Irrigation Gun
S. Bittman, AAFC 2002
Land Application Practices
to Minimize GHG emissions
AERWAY
Sub-Surface Deposition
(SSD) manure applicator
S. Bittman, AAFC 2002
Land Application Practices
to Minimize GHG emissions
Yetter Avenger injector with wings
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Injection slot backfilled, reducing N volatilization losses
Bonnie Ball-Coelho, AAFC, 2002
Land Application Practices
to Minimize GHG emissions
Solid Manures (incl. composts)
Apply
uniformly
 Avoid
clumps – possible anaerobic zone
Incorporate
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Minimize volatilization
Match
applied nutrients to crop needs
 Amounts
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promptly
& Timing
Apply under well-aerated conditions
Minimize compaction
 Avoid application just before/after rain
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Some General Principles
Conserve & re-cycle nutrients
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Don’t promote N losses (NH3, reduction to N2) to solve other
management issues
Manage nutrients on entire system basis
- incl. energy / ghg impacts of producing new fertilizers
Recycling livestock nutrients reduces need for
new mineral fertilizers
Minimize water additions for handling manure
Reduce odour problems
 Reduce storage/handling/transportation costs
 Reduce environmental risks at application time
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Summary
Collection/ Handling/Storage
Remove quickly from barn to separate storage
 Reduces
odour production (ammonia losses)
 Reduces chances for explosions or corrosion
 Improves air quality – health, productivity
 Conserves nutrients
Cover Lagoons
 Reduces
odour & ghg emissions
Summary
Treatment
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Use enclosed vessels
 Minimize
nutrient losses
 Minimize ghg & odour emissions
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Keep pH near 7.0 – minimize ammonia losses
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Best - Composting or anaerobic digestion
 Minimize
ghg and ammonia emissions
 Reduce pathogens
 Consistent end-product
Summary
Land Application
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Match applied nutrients to crop needs
 Amounts
& Timing
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Apply uniformly, inject liquid manures
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Apply under well-aerated conditions
 Minimize
compaction
 Avoid application just before/after rain